GP 1200 compression question

Just bought a Cool Head by Pro design for my 99 GP1200 npv. I'm trying to achieve the 140psi to 160psi range. The head came with 30cc domes said to bring me up to 215psi. Does anyone have any input to what size domes I should get to achieve my desired compression? By the way the engine is a stock bore 1200 non pv.
Thanks